The present invention relates to a method of applying and distributing a charge of a particulate material onto a top surface of a substrate, such as a pizza batter. The present invention further relates to an apparatus for the application and distribution of the charge of the particular material onto the top surface of the substrate, such as a pizza batter.
Within the technique, several technical solutions for the application and distribution of a charge such as a charge of a specific foodstuff constituent or a mixture of different foodstuff constituents are known, in particular in relation to the production of pizzas as the particulate material is to be applied onto a pizza batter. Examples of the prior art techniques of applying and distributing a charge of a particulate onto a pizza batter are described in EP 0 787 431 and EP 0 947 137. According to the technique known from EP 0 787 431, a swiftly operated iris opener is stated to allow for the even distribution of the particulate material onto the pizza batter provided the material is initially evenly distributed on the iris opener as the material is stated to be evenly distributed onto the pizza batter provided the iris opener is swiftly shifted from its closed state to its open state. The swift opening of the iris opener calls for an extreme mechanical impact to the particulate material and also an excessive force impact to the iris opener which iris opener is also subjected to being jammed or otherwise blocked provided the particulate material be jammed between the individual plate elements of the iris opener. According to the technique known from EPO 947 137, the particulate material is stated to be evenly distributed on the pizza batter by the utilization of baffle and guide plates which are stated to provide an adequate and sufficient distribution of the material as the material is simply allowed to drop out from an overhead container and into contact with a baffle and guiding plate. It has, however, turned out that the even distribution of the material onto the pizza batter cannot be accomplished through the utilization of simple baffle and guide plates as the material inevitably is collected at specific locations below the baffle or guide plates rather than being evenly distributed.
It is an object of the present invention to provide a simple and reliable technique for the application and distribution of a particulate material onto an underlying substrate such as the distribution of particulate foodstuff onto a pizza batter which technique on the one hand ensures an even distribution of the particulate material onto the underlying substrate and on the other hand exposes the particulate material to a minimum of physical impact as compared to the prior art iris opening technique and the technique of allowing the material to fall a substantial distance before contacting a guiding plate such as a baffle or guide plate.
It is a further feature of the present invention that the technique of applying and evenly distributing a particulate material onto an underlying substrate also causes a minimum wear to the components of the apparatus and further provides a delicate and minimum force impact to the particulate material to be applied and evenly distributed onto the underlying substrate.
The above object and the above feature together with numerous other objects, features and advantages which will be evident from the below detailed description of the presently preferred embodiments of the technique according to the present invention are in accordance with the teachings of the present invention obtained by a method of applying and distributing a charge of a particulate material onto a top surface of a substrate, such as a pizza batter, comprising:
providing the charge,
delivering the charge onto a movable vibrational surface having an area exceeding the area of the substrate, the surface being positioned above and in registration with the substrate,
keeping the charge on the vibrational surface within a specific area corresponding to the area of the substrate by means of an encircling guide defining the specific area and having at its lower end a flexible skirt for contacting and sealing against the vibrational surface,
vibrating the vibrational surface for causing the charge received on the vibrational surface and kept within the specific area to be evenly and randomly distributed within the area, and
transferring the charge from the vibrational surface onto the substrate by moving the vibrational surface away from the position above and in registration with the substrate while vibrating the vibrational surface for allowing the charge evenly and randomly distributed within the specific area of the vibrational surface to drop onto the substrate.
According to the teachings of the present invention, the application of the particulate material onto the underlying substrate is established in a combined vibrational and vibrational surface moving operation. As the material is vibrated by means of the vibrational surface and as the vibrational surface is moved away from its position above and in registration with the underlying substrate, the particulate material is merely exposed to the mechanical impact by the vibration of the material rather than the falling through an assembly including baffle and guide plates or alternatively the swiftly opening of an iris opener. Still according to the teachings of the present invention, the utilization of the vibrational surface and the movement of the vibrational surface away from the position above and in registration with the substrate and keeping the charge of the particulate material within the encircling guide in combination provides an adequate and even distribution of the charge of the particulate material onto the top surface of the underlying substrate and at the same time exposes the particulate material to a minimum physical impact.
Although the charge of particulate material to be distributed onto the underlying substrate in accordance with the teachings of the present invention may be provided in any adequate manner by means of any mechanical means such as a conveyer belt, the charge is in accordance with the presently preferred embodiment of the method according to the present invention preferably provided from an overhead charge distributor such as an overhead openable hopper for ensuring that the charge is readily introduced into the specific area defined by the encircling guide and through the vibration of the vibrational surface caused to be evenly distributed on said specific area.
The vibrational surface may in accordance with the teachings of the present invention be constituted by any solid or pliable means such as a moveable plate or alternatively and preferably a flexible and foldable foil or web commonly known within the technical field as a shuttle conveyor belt. Through the utilization of a shuttle conveyor belt constituting the vibrational surface, a simple and reliable and further wear-resistant means is provided fulfilling the purpose of the vibrational surface of on the one hand providing the even distribution of the particulate material onto the underlying substrate and on the other hand exposing the particulate material to a minimum mechanical impact or influence.
The technique of applying and distributing a charge of a particulate material onto the top surface of a substrate according to the method of the present invention may be established by moving the vibrational surface and the cooperating encircling guide into a position above the pizza batter, however, according to the presently preferred embodiment of the method according to the present invention, the substrate is preferably positioned in registration with the encircling guide as the method may advantageously further comprise the step of arranging the substrate in the position below and in registration with an encircling guide before starting vibrating the vibrational surface and moving the vibrational surface away from the above-mentioned position above and in registration with the substrate for establishing the transfer of the charge from the vibrational surface onto the substrate.
In order to guarantee that the particulate material which is allowed to drop onto the substrate from the vibrational surface as the vibrational surface is moved away from its position above and in registration with the substrate, the method according to the present invention preferably further comprises the step of positioning a further encircling guide circumpherentially encircling the substrate while transferring the charge from the vibrational surface onto the substrate and raising the further encircling guide for allowing the substrate to be removed after the transfer of the charge to the substrate.
The present invention further relates to as stated above an apparatus for applying and distributing a charge of a particulate material onto the top surface of a substrate such as a pizza batter. The above object, the above features together with numerous other objects, features and advantages which will be evident from the below detailed description of the presently preferred embodiments of the technique according to the present invention are in accordance with the teachings of the present invention obtained by an apparatus for applying and distributing a charge of a particulate material onto a top surface of a substrate, such as a pizza batter, comprising:
a delivery means for delivering such charge
a movable vibrational surface having an area exceeding the area of the substrate, the surface being positioned above and in registration with the substrate, and further being positioned below the delivery means for receiving the charge from the delivery means,
an encircling guide means for keeping the charge on the vibrational surface within a specific area corresponding to the area of the substrate, the encircling guide defining such specific area and having at its lower end a flexible skirt for contacting and sealing against the vibrational surface,
a vibration generating means for vibrating the vibrational surface for causing the charge received on the vibrational surface and kept within the specific area defined by the encircling guide to be evenly and randomly distributed within the area, and
a motion generating means for moving the vibrational surface away from the position above and in registration with the substrate while vibrating the vibrational surface for allowing the charge evenly and randomly distributed within the specific area of the vibrational surface to drop onto the substrate thereby transferring the charge from the vibrational surface onto such substrate.
The apparatus according to the present invention may further advantageously be implemented in accordance with above described advantageous and preferred embodiments of the method according to the present invention. Still further, the vibrational surface of the apparatus according to the present invention may preferably be vibrated at a frequency of frequency of 1-25 Hz such as 2-20 Hz, e.g. 3-15 Hz, such as 6-12 Hz further preferably approximately 10 Hz.
According to the teachings of the present invention, the amplitude of the vibration to which the particulate material be exposed while vibrating the vibrational surface may be adapted or adjusted to the material in question for preventing the particulate material to be exposed to excessive physical impact, provided the particulate material be a delicate particulate material such as certain groceries. In the presently preferred embodiment of the apparatus according to the present invention, the amplitude (RMS: Root Mean Square) of the vibration of the vibrational surface is of the order of 1-20 mm, such as 3-12 mm, preferably approximately 10-12 mm, the vibrational impact being of a sinusoidal configuration or alternatively any other configuration.